ode 45 and for loop

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Tuur Vanderhaegen
Tuur Vanderhaegen 2020-11-23
评论： Tuur Vanderhaegen 2020-11-23
Hi,
I would like to use a for loop for a constant value i in my diff.eq. but I don't know how to implement it. Also I would like to have the matrices X and T for al the values of i.
for i : 0.1:0.1:10
[T,X] = ode45(@fx, [0 4], [0 0]) %Can I implement i here and give the matrices X and T an index?
end
function dx = fx(t,x) % Can I give i as an input here.
rho = 1.225;
C_w = 0.3;
A = 0.005;
m = 0.314;
C_r = 0.035;
R_T = 0.7;
n_0 = 378.33;
i = 1;
T_stall = 0.1868;
r = 0.030;
dx = zeros (2,1);
dx(1) = x(2);
dx(2) = (-T_stall * R_T * i^2 * ((1000 * x(2)/ pi ) - n_0/i)/(n_0 * r) - m * 9.81 * C_r - 0.5 * rho * A * C_w * x(2)^2)/m;
% the diff. eq. with i
end

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采纳的回答

Stephan
Stephan 2020-11-23
k = 0;
T_sol = cell(1,100);
X_sol = cell(1,100);
for ii = 0.1:0.1:10
k = k+1;
[T,X] = ode45(@(t,x)fx(t,x,ii), [0 4], [0 0]);
T_sol{k} = T;
X_sol{k} = X;
end
% plot first and last solution
plot(T_sol{1}, X_sol{1})
hold on
plot(T_sol{100}, X_sol{100})
hold off
function dx = fx(~,x,ii) % Can I give i as an input here.
rho = 1.225;
C_w = 0.3;
A = 0.005;
m = 0.314;
C_r = 0.035;
R_T = 0.7;
n_0 = 378.33;
T_stall = 0.1868;
r = 0.030;
dx = zeros (2,1);
dx(1) = x(2);
dx(2) = (-T_stall * R_T * ii.^2 * ((1000 * x(2)/ pi ) - n_0/ii)/(n_0 * r) - m * 9.81 * C_r - 0.5 * rho * A * C_w * x(2)^2)/m;
% the diff. eq. with i
end

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